What you believe to be truth, will be truth for you for however long you believe it.

What you doubt to be true will always give you more doubt to doubt its truth.

Whether you think you can or you cant you're right.

Those that think the world is a living hell will see and experience a living hell.
While those that believe the world is heaven will see and experience just that.

Your perception creates your reality.

https://en.wikipedia.org/wiki/Double-slit_experiment